I haven't played on Spirocores for a long time but I recently put some used Superflexibles on my bass and I'm finding them to be much easier to bow than the Animas that were on previously. Animas have a somewhat gut-like response and tone for both pizz and arco. The arco is doable but they're slow starting and hard to control. I find the A and E to be worse than the D and G in this regard,too. The arco tone has that grainy, throaty quailty that gut gives, but it's not anywhere as sweet as say Olive/Eudoxa. Anima shines much more for pizz.
Bowing on strings like Flexocore, Helicore Orch., BelCanto or Corelli is much easier and more satisfying. The tone is rich, they start quickly, string crossings are smooth, the bow doesn't slip and slide. But none of those are fabulous for pizz..
My memory of bowing on Spirocore was that the tone was scratchy and there was a bit of that slip and slide, like the bow didn't really grab the string all that well. The Superflexibles are better for me, and I like their pizz too.
To you Spiro fans, what advantages do they have over Superflexibles?